Smell in 70s house during renovation

[Th236]

We are renovating a 1.5-story house built in '74 with a cold attic. During the house viewing, we didn't notice any disturbing odor. The house was more or less original when purchased, but there were no major remarks in the inspection other than most things being past their technical lifespan.
We are renovating the entire house, and now during the renovation, it has started to smell like a cabin. At the entrance and kitchen where the ceiling is open.
We have replaced all the drywall, removed all the old plastic mats, and sanded clean underneath. Upstairs to chipboard and downstairs to concrete to get rid of all the glue residue from the plastic mats, etc.
We have installed underfloor heating on both levels and floated on top. Removed all electric elements and replaced them with an air/water heat pump. Windows will be replaced, etc. Sills have been replaced, of course, and new insulation + drywall about 60 cm above the sills due to possible odor contamination. The moisture content of the sills was okay when replaced.

The attic smells musty, and in phase 2, we will replace the insulation and review the roof.

The musty smell, typical "cabinet smell," is most noticeable where the ceiling is still open and out towards the attic. Could it be this smell that has come down into the house now that it's been open due to all the electrical and plumbing work? Will it disappear when a new vapor barrier + ceiling is in place, I wonder? Starting to get a bit worried😅 it doesn't smell much, but you can sense the smell, and that's not desirable.

 

[jawen]

What is the foundation the house is built on, slab on grade?

There were indeed some materials used during the 70s (and even today) that don't smell "sweet".
Tetex, Masonite & various insulations are those that can smell from "factory."

Then there were certain wooden details that were treated and react if kept moist.
Not all old problems were just in the sill.

 

[Th236]

What is the foundation of the house, slab on grade?

There were some materials that don't smell "pleasant" used during the 70s (and even today).
Tetex, Masonite & different insulations are those that can smell "factory-like".

Then there were certain wood details that were treated & react if they are kept moist.
Not all old problems were just in the sill.

It is slab on grade.

Exactly—a lot to keep track of. I'm thinking that there might also be some negative pressure in the house and the smell is being sucked in?

But do you think that when we close everything up (as mentioned, the ceiling is still open in the laundry room/hall/kitchen where it smells) the smell will stop, or will it still smell as it did when we bought it, which wasn't significant?

On floor 2, where we've started closing things up and laid floors, there's no smell at all, only locally where the ceiling is still open.

 

[jawen]

It is slab on grade.

Is it then a raised floor with heating coils flowed into it, or is it pure concrete slab?
Insulation was almost never used under the slab in the 70s, and if so, floor heating will create "capillary pressure" & draw up moisture from underneath the slab. (warm air rises)

Exactly, a lot to keep track of. Thinking that there might also have been a bit of negative pressure in the house and odor sucked into the house?

You rarely get negative pressure as the fresh air vents in the house create "balance"

 

[Th236]

Is it then a raised floor that you have then poured heating coils into, or is it just a concrete slab?
They almost never used insulation under the slab in the '70s, and if that's the case, floor heating will create "capillary pressure" and draw up moisture from underneath the slab. (warm air rises)


You rarely get negative pressure since the fresh air vents in the house create "balance."

No, sanded down to concrete. The ones who installed the floor coils talked about it with insulation and concrete slab. I think they put insulation in between or something like that for it to be effective. But maybe I misunderstood as well. The floor heating is not yet on since we recently moved. So I don't think it's related to the smell...

Okay - good, maybe I can at least rule out negative pressure.

 

[jawen]

No, sanded down to concrete. Those who laid the floor loops talked about it with insulation and concrete slab. I think they put insulation in between or something like that for it to be good.

You really should find out exactly how the slab is constructed, otherwise you risk lots of follow-up problems.

They may have dismantled the entire raised floor, all the wooden wedges, etc., and then sanded the concrete clean & flat with a Dianova. But my gut feeling says that this is hardly likely because it's an enormously big job, so I'm skeptical about this.

 

[Th236]

You should really find out exactly how the slab is constructed, you risk plenty of follow-up problems otherwise.

They might have dismantled the entire raised floor, all the wooden wedges, etc., and then sanded the concrete clean & flat with a Dianova.
But my gut feeling says that this is hardly likely because it's an enormously big job, so I feel skeptical about this.

No, I don't think so. Now I'm really worried...

But I still don't think that's the source of the smell today since the underfloor heating isn't on.

 

[jawen]

But still, I don't think they are the source of the smell today since the underfloor heating is not on.

No, it probably isn't.

The question is also how they have done under all the interior walls?
Raised floors can often run under interior walls, so "old" material may be left & smell.

 

[Th236]

No, it's probably not that.

The question is also how they have done under all the inner walls?
Raised floors can often run under the inner walls, so "old" material can remain there & smell.

That could be the case. We simply have to hope it disappears when they close up the ceiling. As mentioned, it only smells there and feels like it comes from the ceiling/attic. It's not much of a smell and nothing that sticks to the clothes either, just a faint local scent. I'm very sensitive and builders and other friends who have been there haven't reacted and think it smells more like filler/paint/construction.

 

[som_swahn]

Check to make sure the attic is not too airtight. You haven't noticed any moisture problems up there? I might have missed something in the discussion, but how is the ventilation?

 

[Th236]

check to make sure the attic isn't too tightly sealed. you haven't noticed any moisture problems up there? I might have missed something in the discussion but how is the ventilation?

Attic is original cold attic. No moisture as far as we've noticed or has been noted by inspections. Where I notice the smell is where the knee wall towards the kitchen + laundry room is open. It smells like a typical old attic. As I said, we are going to fix the attic, replace and add insulation or whatever is recommended and also replace the roof. As it is today, I don't want to store things in the attic due to the smell. Same as I'm sensing now in the kitchen/laundry room.

Ventilation is natural draught. We have had ventilation experts there who helped us review, so it feels like a good plan there. As I said, it's mostly me who reacts to the smell. My partner thinks I'm exaggerating. But it's my nightmare when you spend so much time and money for there to be a smell... it doesn't matter how nice it is then...

 

[som_swahn]

Sounds like you've thought it through, I believe the smell will clear out with time. I can personally relate to this from when moving into places where time has "stood still" for a while, so to speak. Creating a draft has worked for me and apart from appropriate renovations, waiting out the time, but of course, it's more difficult in winter... it's not uncommon to have odors in a transitional period, and if others aren't reacting significantly, I wouldn't worry, just try to accept the current situation and keep working on achieving the standard you desire for the house.

 

[Th236]

sounds like you've thought it through, I think the smell will clear out over time. I recognize it myself from when I've moved into a place where "time has stood still" for a long period, so to speak. Creating a cross draft has worked for me and, apart from appropriate renovations, waiting out the time. But of course, it's more challenging in the winter... It's not uncommon to have odors during a transitional period, and if others don't react significantly, I wouldn't worry. Just try to accept the current situation and keep working towards achieving the standard you want for the house.

I really hope so! I guess I just have to let go of my worries for the moment and evaluate over time, simply. We don't live there today, so when we move in the spring, we'll create a cross draft and hope it disappears 🙏🏼

Thank you for your tips and advice!

 

[Th236]

Update:
Now that all the old materials have been replaced, and new in and out air ventilation is installed, all the smell I sensed is gone. The ceiling inside is also closed. Now it just smells newly built/neutral🙏🏼